It is one of the major ostensible "states" practitioners strive to reach on their way up what the Scientologists call the Bridge to Total Freedom.
Scientology followers are given the status of Clear when a person is deemed to be free of the influence of engrams – unwanted emotions or painful traumas which are not readily available to the conscious mind.
Scientologists believe that human beings accumulate anxieties, psychosomatic illnesses, and aberration due to receiving engrams throughout their current or past lives, and that by applying Dianetics, every single person can obtain the status of Clear.
[6] Hubbard states that merely knowing what the cognition is does not have the effect of realizing it for oneself: Now, we've known for a long time that a thetan made up his own bank (reactive mind), but telling him so didn't get him over it.
[7]Hubbard described Clears as having "an awareness which can create energy at will, and can handle and control, erase or re-create an analytical or reactive mind".
Hubbard claimed that Clears have complete memories and know why events in their lives have happened, which leaves them free to pursue their goals without hindrances (the "reactive mind") emanating from past experiences.
The Church of Scientology claims that if all individuals in the world were “Clear”, the world would be “free of drugs, war, pollution, crime, mental illness and other ills.”[9] After attaining the state of Clear, a person may go on to study the Operating Thetan levels, which are described in Scientology materials as states where the ability to operate outside the body via "exteriorization" becomes commonplace.
In August 1950, amidst the success of Dianetics, Hubbard held a demonstration in Los Angeles' Shrine Auditorium where he presented a young woman called Sonya Bianchi to a large audience including many reporters and photographers as "the world's first Clear."
Science-fiction author Arthur Jean Cox's April 1952 letter to skeptic Martin Gardner would later claim that the event was a "fiasco", which Gardner repeated: "in the demonstration that followed, she failed to remember a single formula in physics (the subject in which she was majoring) or the color of Hubbard's tie when his back was turned.